BIOGEN INC

Ticker: BIIB CUSIP: 09062X103 Class: COM

CITADEL ADVISORS LLC's Holding History (CIK: 0001423053)

Note: Option positions (PUT/CALL) are excluded.

Q4 2025

Shares 40,424 Value ($000) $7,114 Avg Close $163.37 Range $138.00 - $185.17

Q3 2025

Shares 372,728 Value ($000) $52,212 Avg Close $135.17 Range $121.05 - $150.28

Q2 2025

Shares 608,590 Value ($000) $76,433 Avg Close $124.60 Range $110.04 - $137.32

Q1 2025

Shares 541,764 Value ($000) $74,135 Avg Close $142.96 Range $128.51 - $157.09

Q4 2024

Shares 153,660 Value ($000) $23,498 Avg Close $168.67 Range $145.07 - $195.00

Q3 2024

Shares 372,366 Value ($000) $72,179 Avg Close $209.21 Range $188.78 - $238.00

Q1 2024

Shares 149,298 Value ($000) $32,193 Avg Close $234.20 Range $211.02 - $268.30

Q4 2023

Shares 5,261 Value ($000) $1,361 Avg Close $245.62 Range $220.86 - $269.43

Q3 2023

Shares 78,136 Value ($000) $20,082 Avg Close $267.47 Range $251.85 - $287.60

Q1 2023

Shares 245,084 Value ($000) $68,141 Avg Close $276.70 Range $254.80 - $295.90

Q4 2022

Shares 247,812 Value ($000) $68,624 Avg Close $282.44 Range $250.31 - $311.88

Q3 2022

Shares 249,378 Value ($000) $66,584 Avg Close $212.38 Range $193.65 - $283.44

Q2 2022

Shares 208,443 Value ($000) $42,510 Avg Close $204.43 Range $187.16 - $225.50

Q1 2022

Shares 78,395 Value ($000) $16,510 Avg Close $217.46 Range $192.67 - $249.00

Q4 2021

Shares 89,241 Value ($000) $21,411 Avg Close $257.12 Range $221.72 - $290.76

Q3 2021

Shares 336,356 Value ($000) $95,185 Avg Close $327.75 Range $282.64 - $372.12

Q2 2021

Shares 556,889 Value ($000) $192,834 Avg Close $302.94 Range $257.03 - $468.55

Q1 2021

Shares 223,563 Value ($000) $62,541 Avg Close $269.69 Range $238.40 - $296.38

Q4 2020

Shares 349,894 Value ($000) $85,675 Avg Close $259.08 Range $223.25 - $363.92

Q3 2020

Shares 23,609 Value ($000) $6,697 Avg Close $278.91 Range $261.87 - $312.00

Q2 2020

Shares 138,265 Value ($000) $36,993 Avg Close $300.59 Range $257.60 - $350.24

Q1 2020

Shares 212,903 Value ($000) $67,358 Avg Close $303.47 Range $262.25 - $374.99

Q4 2019

Shares 229,597 Value ($000) $68,128 Avg Close $277.46 Range $219.70 - $318.00

Q3 2019

Shares 144,182 Value ($000) $33,568 Avg Close $232.85 Range $215.78 - $246.99

Q2 2019

Shares 15,109 Value ($000) $3,534 Avg Close $230.90 Range $219.20 - $245.35

Q1 2019

Shares 149,416 Value ($000) $35,319 Avg Close $314.89 Range $216.12 - $344.00

Q4 2018

Shares 136,179 Value ($000) $40,979 Avg Close $319.14 Range $278.46 - $358.41

Q3 2018

Shares 55,500 Value ($000) $19,609 Avg Close $344.30 Range $288.13 - $388.67

Q2 2018

Shares 115,134 Value ($000) $33,417 Avg Close $281.15 Range $249.17 - $310.91

Q1 2018

Shares 259,367 Value ($000) $71,020 Avg Close $310.41 Range $259.76 - $370.57

Q4 2017

Shares 160,964 Value ($000) $51,278 Avg Close $320.80 Range $301.81 - $348.84

Q3 2017

Shares 663,696 Value ($000) $207,817 Avg Close $296.11 Range $269.50 - $330.00

Q2 2017

Shares 1,066,566 Value ($000) $289,423 Avg Close $264.42 Range $244.28 - $291.90

Q1 2017

Shares 791,282 Value ($000) $216,352 Avg Close $282.75 Range $260.50 - $301.42

Q4 2016

Shares 581,732 Value ($000) $164,967 Avg Close $296.43 Range $268.00 - $329.83

Q3 2016

Shares 807,540 Value ($000) $252,784 Avg Close $296.18 Range $240.07 - $333.65

Q2 2016

Shares 1,358,326 Value ($000) $328,470 Avg Close $263.54 Range $223.02 - $292.69

Q1 2016

Shares 339,068 Value ($000) $88,265 Avg Close $264.15 Range $242.07 - $301.02

Q4 2015

Shares 647,371 Value ($000) $198,322 Avg Close $287.35 Range $254.00 - $311.65

Q3 2015

Shares 591,889 Value ($000) $172,719 Avg Close $330.23 Range $265.00 - $412.24

Q2 2015

Shares 443,736 Value ($000) $179,243 Avg Close $401.33 Range $368.88 - $432.88

Q1 2015

Shares 106,943 Value ($000) $45,156 Avg Close $394.14 Range $334.40 - $480.18

Q4 2014

Shares 82,341 Value ($000) $27,950 Avg Close $323.51 Range $290.85 - $361.93

Q3 2014

Shares 57,178 Value ($000) $18,915 Avg Close $329.72 Range $298.31 - $349.00

Q2 2014

Shares 35,566 Value ($000) $11,215 Avg Close $300.97 Range $272.02 - $322.25

Q1 2014

Shares 140,853 Value ($000) $43,083 Avg Close $317.43 Range $270.62 - $358.89

Q4 2013

Shares 107,132 Value ($000) $29,971 Avg Close $258.65 Range $221.07 - $298.82

Q3 2013

Shares 11,668 Value ($000) $2,809 Avg Close $223.81 Range $203.55 - $248.95

Q2 2013

Shares 3,615 Value ($000) $778 Avg Close $213.68 Range $191.80 - $242.64

Period	Shares	Value ($000)	Average Close	Price Range
Q4 2025	40,424	$7,114	$163.37	$138.00 - $185.17
Q3 2025	372,728	$52,212	$135.17	$121.05 - $150.28
Q2 2025	608,590	$76,433	$124.60	$110.04 - $137.32
Q1 2025	541,764	$74,135	$142.96	$128.51 - $157.09
Q4 2024	153,660	$23,498	$168.67	$145.07 - $195.00
Q3 2024	372,366	$72,179	$209.21	$188.78 - $238.00
Q1 2024	149,298	$32,193	$234.20	$211.02 - $268.30
Q4 2023	5,261	$1,361	$245.62	$220.86 - $269.43
Q3 2023	78,136	$20,082	$267.47	$251.85 - $287.60
Q1 2023	245,084	$68,141	$276.70	$254.80 - $295.90
Q4 2022	247,812	$68,624	$282.44	$250.31 - $311.88
Q3 2022	249,378	$66,584	$212.38	$193.65 - $283.44
Q2 2022	208,443	$42,510	$204.43	$187.16 - $225.50
Q1 2022	78,395	$16,510	$217.46	$192.67 - $249.00
Q4 2021	89,241	$21,411	$257.12	$221.72 - $290.76
Q3 2021	336,356	$95,185	$327.75	$282.64 - $372.12
Q2 2021	556,889	$192,834	$302.94	$257.03 - $468.55
Q1 2021	223,563	$62,541	$269.69	$238.40 - $296.38
Q4 2020	349,894	$85,675	$259.08	$223.25 - $363.92
Q3 2020	23,609	$6,697	$278.91	$261.87 - $312.00
Q2 2020	138,265	$36,993	$300.59	$257.60 - $350.24
Q1 2020	212,903	$67,358	$303.47	$262.25 - $374.99
Q4 2019	229,597	$68,128	$277.46	$219.70 - $318.00
Q3 2019	144,182	$33,568	$232.85	$215.78 - $246.99
Q2 2019	15,109	$3,534	$230.90	$219.20 - $245.35
Q1 2019	149,416	$35,319	$314.89	$216.12 - $344.00
Q4 2018	136,179	$40,979	$319.14	$278.46 - $358.41
Q3 2018	55,500	$19,609	$344.30	$288.13 - $388.67
Q2 2018	115,134	$33,417	$281.15	$249.17 - $310.91
Q1 2018	259,367	$71,020	$310.41	$259.76 - $370.57
Q4 2017	160,964	$51,278	$320.80	$301.81 - $348.84
Q3 2017	663,696	$207,817	$296.11	$269.50 - $330.00
Q2 2017	1,066,566	$289,423	$264.42	$244.28 - $291.90
Q1 2017	791,282	$216,352	$282.75	$260.50 - $301.42
Q4 2016	581,732	$164,967	$296.43	$268.00 - $329.83
Q3 2016	807,540	$252,784	$296.18	$240.07 - $333.65
Q2 2016	1,358,326	$328,470	$263.54	$223.02 - $292.69
Q1 2016	339,068	$88,265	$264.15	$242.07 - $301.02
Q4 2015	647,371	$198,322	$287.35	$254.00 - $311.65
Q3 2015	591,889	$172,719	$330.23	$265.00 - $412.24
Q2 2015	443,736	$179,243	$401.33	$368.88 - $432.88
Q1 2015	106,943	$45,156	$394.14	$334.40 - $480.18
Q4 2014	82,341	$27,950	$323.51	$290.85 - $361.93
Q3 2014	57,178	$18,915	$329.72	$298.31 - $349.00
Q2 2014	35,566	$11,215	$300.97	$272.02 - $322.25
Q1 2014	140,853	$43,083	$317.43	$270.62 - $358.89
Q4 2013	107,132	$29,971	$258.65	$221.07 - $298.82
Q3 2013	11,668	$2,809	$223.81	$203.55 - $248.95
Q2 2013	3,615	$778	$213.68	$191.80 - $242.64